Refine your search:

Containing Text
- - -
+
Filter by author or institution
GO
Filter by publication date
From:
October, 2006
Until:
Today
Filter by section
 
 
Metals, Light: Metals with low specific gravity, typically smaller than 5, characterized by a single valence (1, 2, or 3), a simple spectrum, strong electromotive force (positive), and colorless compounds. (From Grant & Hackh's Chemical Dictionary, 5th ed)
 Science Education: Essentials of General Chemistry

Coordination Chemistry Complexes

JoVE Science Education

Source: Laboratory of Dr. Neal Abrams — SUNY College of Environmental Science and Forestry

Transition metals are found everywhere from vitamin supplements to electroplating baths. Transition metals also make up the pigments in many paints and compose all minerals. Typically, transition metals are found in the cationic form since they readily oxidize, or lose electrons, and are surrounded by electron donors called ligands. These ligands do not form ionic or covalent bonds with the metal center, rather they take on a third type of bond known as coordinate-covalent. The coordinate-covalent bond between a ligand and a metal is dynamic, meaning that ligands are continuously exchanging and re-coordinating around the metal center. The identities of both the metal and the ligand dictates which ligands will bond preferentially over another. In addition, color and magnetic properties are also due to the types of complexes that are formed. The coordination compounds that form are analyzed using a variety of instruments and tools. This experiment explores why so many complexes are possible and uses a spectrochemical (color and chemical) method to help identify the type of coordination complex that forms.

 JoVE Engineering

Integration of Light Trapping Silver Nanostructures in Hydrogenated Microcrystalline Silicon Solar Cells by Transfer Printing

1Renewable Energy Research Center, Fukushima Renewable Energy Institute, National Institute of Advanced Industrial Science and Technology, Koriyama, Fukushima, Japan, 2Research Center for Photovoltaic Technologies, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan


JoVE 53276

 JoVE Environment

Removal of Trace Elements by Cupric Oxide Nanoparticles from Uranium In Situ Recovery Bleed Water and Its Effect on Cell Viability

1Division of Physical Therapy, Department of Orthopedics & Rehabilitation, University of New Mexico, 2Department of Ecosystem Science and Management, University of Wyoming, 3School of Pharmacy, University of Wyoming, 4Department of Environmental and Radiological Health Sciences, Colorado State University, 5Center for Environmental Medicine, Colorado State University, 6College of Pharmacy, California Northstate University


JoVE 52715

 JoVE Bioengineering

Fabrication of a Dipole-assisted Solid Phase Extraction Microchip for Trace Metal Analysis in Water Samples

1Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 2Center for Measurement Standards, Industrial Technology Research Institute, 3National Synchrotron Radiation Research Center, 4Department of Chemistry, National Changhua University of Education


JoVE 53500

 Science Education: Essentials of General Chemistry

Determining the Solubility Rules of Ionic Compounds

JoVE Science Education

Source: Laboratory of Dr. Neal Abrams — SUNY College of Environmental Science and Forestry

An ionic compound's solubility can be determined via qualitative analysis. Qualitative analysis is a branch of analytical chemistry that uses chemical properties and reactions to identify the cation or anion present in a chemical compound. While the chemical reactions rely on known solubility rules, those same rules can be determined by identifying the products that form. Qualitative analysis is not typically done in modern industrial chemistry labs, but it can be used easily in the field without the need of sophisticated instrumentation. Qualitative analysis also focuses on understanding ionic and net ionic reactions as well as organizing data into a flow chart to explain observations and make definitive conclusions. Many cations have similar chemical properties, as do the anion counterparts. Correct identification requires careful separation and analysis to systematically identify the ions present in a solution. It is important to understand acid/base properties, ionic equilibria, redox reactions, and pH properties to identify ions successfully. While there is a qualitative test for virtually every elemental and polyatomic ion, the identification process typically begi

 JoVE Engineering

Making Record-efficiency SnS Solar Cells by Thermal Evaporation and Atomic Layer Deposition

1Department of Mechanical Engineering, Massachusetts Institute of Technology, 2Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology, 3School of Engineering and Applied Sciences, Harvard University, 4Department of Materials Science and Engineering, Massachusetts Institute of Technology, 5Department of Chemistry & Chemical Biology, Harvard University


JoVE 52705

 Science Education: Essentials of Analytical Chemistry

X-ray Fluorescence (XRF)

JoVE Science Education

Source: Laboratory of Dr. Lydia Finney — Argonne National Laboratory

X-ray fluorescence is an induced, emitted radiation that can be used to generate spectroscopic information. X-ray fluorescence microscopy is a non-destructive imaging technique that uses the induced fluorescence emission of metals to identify and quantify their spatial distribution.

 Science Education: Essentials of Environmental Science

Lead Analysis of Soil Using Atomic Absorption Spectroscopy

JoVE Science Education

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University

Lead occurs naturally in soil, in levels ranging from 10-50 ppm. However, with the widespread use of lead in paint and gasoline in addition to contamination by industry, urban soils often have concentrations of lead significantly greater than background levels – up to 10,000 ppm in some places. Ongoing problems arise from the fact that lead does not biodegrade, and instead remains in the soil. Serious health risks are associated with lead poisoning, where children are particularly at risk. Millions of children in the U.S. are exposed to soil containing lead. This exposure can cause developmental and behavioral problems in children. These problems include learning disabilities, inattention, delayed growth, and brain damage. The Environmental Protection Agency has set a standard for lead in soil at 400 ppm for play areas and 1,200 ppm for non-play areas. Lead is also of concern in soil, when it’s used for gardening. Plants take up lead from the soil. Therefore, vegetables or herbs grown in contaminated soil can lead to lead poisoning. In addition, contaminated soil particles can be breathed in while gardening or brought into the house on clothing and footwear. It is recommended that s

 Science Education: Essentials of Organic Chemistry

Preparing Anhydrous Reagents and Equipment

JoVE Science Education

Source: Laboratory of Dr. Dana Lashley - College of William and Mary
Demonstrated by: Timothy Beck and Lucas Arney

Many reactions in organic chemistry are moisture-sensitive and must be carried out under careful exclusion of water. In these cases the reagents have a high affinity to react with water from the atmosphere and if left exposed the desired reaction will not take place or give poor yields, because the reactants are chemically altered. In order to prevent undesired reactions with H2O these reactions have to be carried out under an inert atmosphere. An inert atmosphere is generated by running the reaction under nitrogen gas, or in more sensitive cases, under a noble gas such as argon. Every component in such a reaction must be completely anhydrous, or free of water. This includes all reagents and solvents used as well as all glassware and equipment that will come into contact with the reagents. Extremely water-sensitive reactions must be carried out inside of a glovebox which provides a completely sealed off anhydrous environment to work under via a pair of gloves which protrudes out to one of the sides of the chamber.

 JoVE Environment

Extraction and Analysis of Microbial Phospholipid Fatty Acids in Soils

1Department of Renewable Resources, University of Alberta, 2Department of Science, Augustana Faculty, University of Alberta, 3Laboratoire Génie Civil et géo-Environnement, Université de Lille, 4Department of Earth and Environmental Sciences, Mount Royal University, 5Forest Ecology & Production, Great Lakes Forestry Centre, Natural Resources Canada


JoVE 54360

 JoVE Bioengineering

Multi-Scale Modification of Metallic Implants With Pore Gradients, Polyelectrolytes and Their Indirect Monitoring In vivo

1Biomatériaux et Bioingénieriee, INSERM, 2Service Oto-Rhino-Laryngologie, Hôpitaux Universitaires de Strasbourg, 3Faculté de Chirurgie Dentaire, Université de Strasbourg


JoVE 50533

 JoVE Medicine

A Murine Model of Stent Implantation in the Carotid Artery for the Study of Restenosis

1Institute for Molecular Cardiovascular Research, RWTH Aachen University, 2Institute for Textile Technology and Mechanical Engineering, RWTH Aachen University, 3Institute for Applied Medical Engineering, Helmholtz-Institute of RWTH Aachen University, 4Department of Experimental Molecular Imaging, RWTH Aachen University, 5Department of Oral and Maxillofacila Surgery, RWTH Aachen University


JoVE 50233

 Science Education: Essentials of Environmental Microbiology

Isolation of Fecal Bacteria from Water Samples by Filtration

JoVE Science Education

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba - Arizona University
Demonstrating Author: Luisa Ikner

The quality of water destined for use in agricultural, recreational, and domestic settings is of great importance due to the potential for outbreaks of waterborne disease. Microbial agents implicated in such events include parasites, bacteria, and viruses that are shed in high numbers in the feces of infected people and animals. Transmission to new and susceptible hosts may then occur via the fecal-oral route upon ingestion of contaminated water. Therefore, the ability to monitor water sources for the presence of pathogenic microorganisms is significant in order to ensure public health. Due to the sheer number and variety of potential fecal-oral pathogens that may be present in water and their variable concentrations, it is impractical and expensive to assay directly for each one of them on a regular basis. Therefore, the microbiological assays for water quality monitoring employ coliform indicator bacteria. Coliforms comprise, in part, the normal intestinal microflora of warm-blooded mammals, are non-pathogenic, and are consistently excreted in the feces. Therefore, the detection of coliform bacteria in water means that a fecal release occurred, and that harmful pathogenic m

12345678963
More Results...
Waiting
simple hit counter